1. Field of the Invention
The present invention relates to an improvement of an electromagnetic fuel injection valve, in which a valve housing includes: a tubular valve seat member having a valve seat in a front end portion thereof; a magnetic cylindrical body coaxially connected to a rear end portion of the valve seat member; a nonmagnetic cylindrical body coaxially and liquid-tightly welded to a rear end of the magnetic cylindrical body; and a hollow cylindrical stationary core coaxially and liquid-tightly welded to a rear end of the nonmagnetic cylindrical body, a valve assembly is housed in the valve housing and includes: a valve body capable of being seated on the valve seat; and a movable core connected to a rear end of the valve body, a suction tubular part projecting toward an inside of the nonmagnetic cylindrical body is provided to a front end portion of the stationary core, and a front end of the suction tubular part and a rear end of the movable core are opposed to each other in the inside of the nonmagnetic cylindrical body, and a method of manufacturing the same.
2. Description of the Related Art
Such an electromagnetic fuel injection valve is known from the Japanese Patent No. 3819907.
The axial dimension of such an electromagnetic fuel injection valve can be decreased by opposing the front end of the suction tubular part of the stationary core and the rear end of the movable core to each other inside the nonmagnetic cylindrical body.
When such an electromagnetic fuel injection valve is manufactured, a valve housing is produced by coaxially welding the valve seat member, the magnetic cylindrical body, the nonmagnetic cylindrical body and the stationary core sequentially. After the valve housing is completed, it is checked whether or not each welded part is satisfactorily liquid-tight. In this check, a fluid pressure is applied to the inside of the valve housing. Thereby, whether or not each welded part is satisfactorily liquid-tight is judged depending on whether or not pressure leaks from each welded part.
However, in the conventional type of electromagnetic fuel injection valve, as disclosed in Japanese Patent No. 3819907, the stationary core is temporarily fixed to the nonmagnetic cylindrical body by press-fitting the suction tubular part of the stationary core into the inner peripheral surface of the nonmagnetic cylindrical body in a step preceding a step of welding the nonmagnetic cylindrical body and the stationary core together. As a result, at the time of a liquid-tightness checking, it takes a considerable time for the fluid pressure to reach the welded part after passing the press-fitted portion, and therefore takes a long time to check whether or not pressure leaks from the welded part. This deteriorates the checking efficiency.